The present invention relates to powder-actuated fastening tools and, more particularly, to a loading device for inserting a fastener in the barrel of such a tool.
Fastener driving tools actuated by the detonation of a blank piece cased or caseless ammunition are well known in the art. Such tools are of two types: "free flight", wherein the expanding gases produced by the detonated ammunition are applied directly against a fastener disposed in the tool barrel, and "piston", wherein a captive piston is disposed in the tool barrel intermediate the ammuniton and the fastener. In this latter type of tool, which is predominant in the marketplace, the piston must be reset from a forward or "fired" position, proximate the tool muzzle, to a rearward or "firing" position, proximate the tool breech, after each fastening. Often, this resetting is achieved by loading a fastener, head portion first, into the tool muzzle and then pressing against the protruding fastener nose or pointed end to force the entire fastener into the tool barrel. During this displacement, the fastener engages the piston, forcing the latter into the previously described "firing" position.
In most "piston" type tools, the piston is equipped with one or more "sealing rings" which slideably engage the bore wall of the tool barrel. These rings act as gas seals and further serve to retain the piston in a desired position within the barrel prior to discharge.
The fastener, likewise, is normally fitted with a washer or guide member which acts to retain the fastener prior to discharge and further serves to center and guide the fastener in its passage through the barrel during setting.
Insertion of a fastener into the tool is thus seen to require that considerable force be exerted against the fastener tip in order to overcome the resisting forces created by the piston rings and the fastener guide member. For this reason, a fastener is most commonly inserted by pressing the tool, with the protruding fastener tip against a hard surface, such as the workpiece. Such an insertion method is often inconvenient and further suffers in that the fastener may not be inserted beyond the point where the fastener tip is flush with the tool muzzle. Further insertion of the fastener, as may be required for the desired placement of the piston, necessitates the use of a separate pusher or ram rod, adding further to the inconvenience of the insertion procedure.
It is therefore, a primary object of the present invention to provide a safe, convenient and economical means of inserting a fastener to a desired position in the barrel bore of a powder-actuated fastening tool.
It is a further object to provide such an insertion means which may be incorporated in presently existing tools with minimal alteration thereof.
The above and other objects, as may hereinafter appear are achieved, in general, by a loading device comprising a ram-equipped, tubular fastener retaining member hingedly carried on legs secured to the tool receiver and forming therewith a four bar linkage, whereby the retaining member may be displaced from a first position, atop or alongside the receiver to a second position, in communication with the barrel bore, whereat the retaining member ram may conveniently be utilized to insert the fastener into the barrel.